1. Field of the Invention
The invention relates to a chain store and a process for unloading the chain store, namely a chain store according to the preamble of claim 1 and a process according to the preamble of claim 4.
The chain store and the process can be used for the temporary storage of products of the same type.
The products may be, for example, chocolate bars which are transported from a production apparatus to at least one packaging apparatus. However, the product may consist not of chocolate bars but of other sweet or nonsweet foods in the form of pieces, for example bakery articles, or of cans or other containers having any filling or of components for mechanical engineering, for example ball bearings, which are transported to a packaging apparatus or other processing apparatus.
2. Description of the Prior Art
In the case of known means for the production and packing of chocolate bars, the bars produced by a production apparatus are transported via a feed belt to chain stores and then through these to packaging apparatuses. Each chain store can be formed, for example, approximately according to DE 90 12 074 U and serves as a compensating apparatus for compensating variations in the feed rate of bars or the packing rate of the packing apparatus and complete stoppages of operation of the production apparatus or of the packing apparatus, for example lasting for 5 min to 45 min. A chain store of this type typically has 150 to about 1200 gondolas attached to two continuous chains and having a plurality of shelves for holding one row of bars each. Each chain is deflected by a plurality of chain wheels mounted in a frame and by a plurality of chain wheels mounted on vertically displaceable carriages and forms a number of loops.
In the case of known chain stores for the temporary storage of articles on gondolas suspended from two chains, those chains of the loading and unloading side which are each driven by a drive motor are intermittently moved, i.e. they are stationary while articles are being loaded onto the shelves at the loading station and are being unloaded again from the shelves at the unloading station. The store operates according to the xe2x80x9cfirst-inxe2x80x9d/xe2x80x9cfirst-outxe2x80x9d principle and makes it possible in particular to operate infeed and outflow at different speeds.
Up to now, a chain store has been emptied at the outflow only at one discharge level, i.e. the product rows are pushed by an ejector from the shelf level onto a discharge belt leading away and are then transported away laterally. This simple arrangement permits a discharge rate of about 30 rows per minute. The chain store operates as follows: as soon as a first shelf reaches the unloading station, the drive motor of the unloading side is switched off or the corresponding drive drum is disengaged from the gear so that the shelf remains stationary at the height of the discharge belt leading away. The articles are then transferred by means of the horizontally displaceable ejector to the continuously moving or, during the transfer, stationary discharge belt, depending on requirements. As soon as this transfer process is complete, the movement of the chains is switched on again so that the next shelf reaches the unloading station and the process described above can be repeated.
These known unloading apparatuses for chain stores have the disadvantage that, for each unloading process during which only one shelf level is unloaded in each case, the corresponding chain drive apparatuses are switched off, with the result that not only is the effective transport speed of the unloading side of the chain store reduced but also disadvantageous rocking movements of the shelves whose suspension apparatuses run over a deflection roller occur.
A further problem is that, with increasing production rate, the loading capacity and unloading capacity of the chain stores also have to be increased. Various solutions have already become known for increasing the loading capacity. In contrast to loading, the goods have to be transported from a rest position of the respective shelf to the discharge belt during unloading, which is possible only by means of an ejector. The unloading frequency is accordingly limited by the time which the ejector requires for returning to the original position for the next ejection, and also by the frequency with which the shelves are transported past the discharge belt.
It is the object of the invention to provide a chain store comprising a novel unloading station which in particular makes it possible to unload the articles relatively rapidly and with the saving of time from the shelves of the store, in order thus to achieve up to 50% higher discharge performance compared with known unloading stations.
This object is achieved by a chain store comprising
a plurality of intermittently movable gondolas which serve for receiving products to be stored and are suspended and fastened on at least one articulated chain running vertically over a plurality of deflection rollers, and at least one shelf which serves for receiving the products, and
at least one unloading station which is arranged on an upward- or downward-moving outer side of the chain store and has transfer means for ejecting the products onto a horizontal discharge belt leading away from the unloading side,
wherein the transfer means has two ejectors for simultaneously ejecting products from in each case two shelves one on top of the other, wherein a storage plate which is fastened with its end facing away from the gondola train to a retaining apparatus and is pivotable from a horizontal into a skew position inclined toward the discharge belt and is displaceable away from the gondola train is provided above the discharge belt, wherein the storage plate has rake-like or comb-like teeth extending toward the gondola train, wherein furthermore a vertical product stop having rake-like or comb-like teeth extending upward is provided and wherein the transfer means, the discharge belt, the storage plate and the product stop are arranged and dimensioned in such a way that, during ejection of the products, the lower product or the lower product row is pushed onto the discharge belt and the upper product or the upper product row is simultaneously pushed onto the horizontal storage plate, and that each tooth of the product stop can be passed over its total length through the space between two adjacent teeth of the storage plate.
A further object of the invention is a process for unloading a chain store as mentioned above, comprising gondolas which have a plurality of shelves for receiving one product row each, wherein, during ejection of in each case two product rows stored one on top of the other, the lower row is pushed onto the discharge belt and the upper row is pushed onto the swivelled-up storage plate, wherein, as soon as there is space on the discharge belt, the storage plate is swivelled down onto the discharge belt and is simultaneously or subsequently drawn through the teeth of the product stop, away from the gondola train, the product row being pushed through the teeth of the product stop onto the discharge belt.